COMPARISON OF SINGLE DOSE AND MULTI-DOSE hCG STIMULATION TESTS

Objective: The human chorionic gonadotropin (hCG) stimulation test is widely used to assess testicular steroidogenesis. This test evaluates Leydig cell function and helps to evaluate testosterone synthesis in testicular enzyme defects, hypogonadism, 46,XY sex-ual development disorders (DSD), and micropenis. This study will compare testosterone responses to a single dose of 5000 IU/m2 and three consecutive days of 1500 IU/m(2) hCG regimens. Materials and Methods: The study evaluated 18 patients who were admitted with micropenis, hypospadias, or undescended testis (Group 1) and 18 patients with a molecular diagnosis of androgen receptor insensitivity (56%) or 5 alpha reductase deficiency (44%) (Group 2). The median (interquartile range; IQR) age of the patients were 1.4 (0.8-4.2) years for Group 1 and 0.7 (0.3-0.8) years for Group 2. Baseline testosterone levels were checked and after a single dose of hCG 5000 IU/m(2) injection into the first group, testosterone levels were observed on day one and day four. In the second group, after the injection of hCG 1500 IU/m(2) for three days, testosterone levels were checked on the fourth day. Results: There was no significant difference in height, weight, BMI SDS, and baseline testosterone levels between groups. Af -ter hCG, stimulation testosterone responses did not vary among the groups. Testosterone levels were increased 40-fold and 40.1-fold on day four compared to the baseline in Group 1 and Group 2. In Group 1, testosterone response was significantly higher on day four compared to day one (p=0.001). Conclusions: The hCG tests performed with a single dose or multidoses showed that there was no difference between tes-tosterone responses and these two tests were applicable. Since the 5000 IU/m(2) hCG test requires fewer injections and is easy to administer, this test may be preferred to an evaluation of the Leydig cell function. For an adequate testosterone response, the researchers suggest measuring testosterone levels on the fourth day after the single dose of 5000 IU/m(2).